• Depression is a mood, but sadness is an emotion.

• Depression stays for a longer period, but sadness is short-lived comparatively.

• Depression can originate from life events, certain medical conditions and some drugs as well, but sadness is mainly due to life events and sometimes due to medical conditions.

• Depression can develop to a mood disorder, but sadness is not a psychological disorder only a natural way of responding to a painful situation.

• A depressed person is emotionally numb sometimes but a sad person is exhausted.

• A depressed person shows self-disgust but a sad person shows self-sympathy.

• A depressed person willfully avoids social interactions but a sad person longs for company but neglects social activities due to the focus on troubles.